51909887 has 2 divisors, whose sum is σ = 51909888. Its totient is φ = 51909886.

The previous prime is 51909883. The next prime is 51909917. The reversal of 51909887 is 78890915.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51909887 - 2² = 51909883 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51909883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25954943 + 25954944.

It is an arithmetic number, because the mean of its divisors is an integer number (25954944).

Almost surely, 2^51909887 is an apocalyptic number.

51909887 is a deficient number, since it is larger than the sum of its proper divisors (1).

51909887 is an equidigital number, since it uses as much as digits as its factorization.

51909887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 47.

The square root of 51909887 is about 7204.8516292843. The cubic root of 51909887 is about 373.0353834666.

The spelling of 51909887 in words is "fifty-one million, nine hundred nine thousand, eight hundred eighty-seven".